All the above features are planned for implementation, so don't worry about us not doing any of them. It's just that there are only so many hours in a day and we want to cover the most important features first. So what feature do you need next most badly in C2? This way we can cover the most important ground earliest of all, so we don't have painful omissions going on for too long.

If you have any other things you think should be done first, post them in a reply!

Behaviours. They make things a lot easier and quicker to implement, such as platforming and eight-direction movement. Plus, users will be able to write their own, and I swear there was a mention on the ability to possibly write behaviours through events. My recommendation would be to implement Custom Movement first, since it's so versatile.

The Image Editor and animations would be a very close second, however, same with fine collisions.